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Numerical simulation of flow field deposition and erosion characteristics around bridge-road transition section

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Journal of Mountain Science 2024年第5期21卷 1491-1508页

作者： zhang Kai wang Zhenghui wang Tao TIAN Jianjin zhang Hailong LIU yonghe College of Civil Engineering Lanzhou Jiaotong UniversityLanzhou 730000China Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China

Wind-sand flow generates erosion and deposition around obstacles such as bridges and roadbeds, resulting in sand damage and endangering railway systems in sandy regions. Previous studies have mainly focused on the flow field around roadbeds, overlooking detailed examinations of sand particle erosion and deposition patterns near bridges and roadbeds. This study employs numerical simulations to analyze the influence of varying heights and wind speeds on sand deposition and erosion characteristics at different locations: the bridge-road transition section(side piers), middle piers, and roadbeds. The results show that the side piers, experience greater accumulation than the middle piers. Similarly, the leeward side of the roadbed witnesses more deposition compared to the windward side. Another finding reveals a reduced sand deposition length as the vertical profile, in alignment with the wind direction, moves further from the bridge abutments at the same clearance height. As wind speeds rise, there’s a decline in sand deposition and a marked increase in erosion around the side piers, middle piers and roadbeds. In conclusion, a bridge clearance that’s too low can cause intense sand damage near the side piers, while an extremely high roadbed may lead to extensive surface sand deposition. hence, railway bridges in areas prone to sandy winds should strike a balance in clearance height. This research provides valuable guidelines for determining the most suitable bridge and roadbed heights in regions affected by wind and sand.

关键词： Sandstorm Flow field Bridge-road transition section Sedimentation erosion Numerical simulation

Guidance strategy of motion camouflage for spacecraft pursuit-evasion game

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Chinese Journal of Aeronautics 2024年第3期37卷 312-319页

作者： Jianqing LI Chaoyong LI yonghe zhang Space Information Research institute Hangzhou Dianzi UniversityHangzhou 310018China College of Electrical Engineering Zhejiang UniversityHangzhou 310027China Key Lab of Microsatellites Chinese Academy of SciencesShanghai 201210China

This work is inspired by a stealth pursuit behavior called motion camouflage whereby a pursuer approaches an evader while the pursuer camouflages itself against a predetermined *** formulate the spacecraft pursuit-evasion problem as a stealth pursuit strategy of motion camouflage,in which the pursuer tries to minimize a motion camouflage index defined in this *** Euler-Hill reference frame whose origin is set on the circular reference orbit is used to describe the *** on the rule of motion camouflage,a guidance strategy in open-loop form to achieve motion camouflage index is derived in which the pursuer lies on the camouflage constraint line connecting the central spacecraft and *** order to dispose of the dependence on the evader acceleration in the open-loop guidance strategy,we further consider the motion camouflage pursuit problem within an infinite-horizon nonlinear quadratic differential *** saddle point solution to the game is derived by using the state-dependent Riccati equation method,and the resulting closed-loop guidance strategy is effective in achieving motion *** are performed to demonstrate the capabilities of the proposed guidance strategies for the pursuit–evasion game scenario.

关键词： Pursuit-evasion problem Motion camouflage Differential game Guidance strategy Orbit control

Nanomaterial‑Based Repurposing of Macrophage Metabolism and Its Applications

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Nano-Micro Letters 2024年第11期16卷 494-528页

作者： Tingting Meng Danfeng he Zhuolei Han Rong Shi Yuhan wang Bibo Ren Cheng zhang Zhengwei Mao Gaoxing Luo jun Den institute of Burn Research Southwest HospitalState Key Laboratory of Trauma and Chemical PoisoningArmy Medical UniversityChongqing 400038People’s Republic of China Department of Breast Surgery Gansu Provincial HospitalLanzhouGansu 730030People’s Republic of China MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China

Macrophage immunotherapy represents an emerging therapeutic approach aimed at modulating the immune response to alleviate disease ***(NMs)have been engineered to monitor macrophage metabolism,enabling the evaluation of disease progression and the replication of intricate physiological signal *** achieve this either directly or by delivering regulatory signals,thereby mapping phenotype to effector functions through metabolic repurposing to customize macrophage fate for ***,a comprehensive summary regarding NM-mediated macrophage visualization and coordinated metabolic rewiring to maintain phenotypic equilibrium is currently *** review aims to address this gap by outlining recent advancements in NM-based metabolic *** initially explore the relationship between metabolism,polarization,and disease,before delving into recent NM innovations that visualize macrophage activity to elucidate disease onset and fine-tune its fate through metabolic remodeling for macrophage-centered ***,we discuss the prospects and challenges of NM-mediated metabolic immunotherapy,aiming to accelerate clinical *** anticipate that this review will serve as a valuable reference for researchers seeking to leverage novel metabolic intervention-matched immunomodulators in macrophages or other fields of immune engineering.

关键词： Immunomodulatory nanomaterial Macrophage polarization Macrophage metabolic reprogramming Immune engineering

A review on DFACS(I):System design and dynamics modeling

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Chinese Journal of Aeronautics 2024年第5期37卷 92-119页

作者： Bohan JIAO Qifan LIU Zhaohui DANG Xiaokui YUE yonghe zhang Yuanqing XIA Li DUAN Qinglei HU Chenglei YUE Pengcheng wang Ming GUO Zhansheng DUAN Bing CUI Chu zhang Xiaodong SHAO School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China Innovation Academy for Microsatellites Chinese Academy of SciencesShanghai 710699China School of Automation Beijing Institute of TechnologyBeijing 100081China institute of Mechanics Chinese Academy of SciencesBeijing 710043China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China School of Automation Science and Engineering Xi’an Jiaotong UniversityXi’an 710049China

The Drag-Free and Attitude Control System(DFACS)is a critical platform for various space missions,including high precision satellite navigation,geoscience and gravity field measurement,and space scientific *** paper presents a comprehensive review of over sixty years of research on the design and dynamics model of ***,we examine the open literature on DFACS and its applications in Drag-Free missions,providing readers with necessary background information on the ***,we analyze the system configurations and main characteristics of different DFACSs,paying particular attention to the coupling mechanism between the system configuration and dynamics ***,we summarize the dynamics modeling methods and main dynamics models of DFACS from multiple perspectives,including common fundamentals and specific ***,we identify current challenges and technological difficulties in the system design and dynamics modeling of DFACS,while suggesting potential avenues for future *** paper aims to provide readers with a comprehensive understanding of the state-of-the-art in DFACS research,as well as the future prospects and challenges in this field.

关键词： Drag-Free DFACS System Design Dynamics Modeling Control design

The influence of proxy selection on global annual mean temperature reconstructions during the Common Era

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Science china Earth Sciences 2024年第8期67卷 2522-2534页

作者： Bao YANG Xia LI Minhui he Feng wang Yesi ZHAO Peng zhang Jianglin wang Frontiers Science Center for Critical Earth Material Cycling School of Geography and Ocean ScienceNanjing UniversityNanjing 210023China Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Centre Eau Terre Environnement Institut National de la Recherche ScientifiqueQuébecQCG1K 9A9Canada GEOTOP Research Centre in the Dynamics of the Earth System MontréalQC H2X 3Y7Canada

The reconstruction of global annual mean temperatures made by the PAGES 2k Consortium in 2019 represents one of the most influential sequences of global climate variability over the Common ***,it is still not clear how the reconstruction can be influenced by the selection of reconstruction methods and the selection of proxy records with different temporal resolutions over different *** adopt a widely used Composite-Plus-Scale method to elucidate the effects of the selection of the proxy records on temperature *** ensure the uniformity of data,different types of proxy records spanning the past~2000 years from the PAGES 2k proxy network were used to investigate the potential effects of proxy selection in hemispheric and global temperature reconstructions during the past two *** long-term trends,spectral characteristics,and volcanic responses of the annual temperatures were studied based on the *** results reveal a significant cooling trend in the global annual mean temperature using both tree-ring and non-tree-ring records during the 1–1850CE period,and show that the cooling exhibits a stronger trend in the Southern hemisphere(SH)than that in the Northern hemisphere(NH).Yet,the long-term trends vary according to different combinations of proxy *** reconstructions based on different types of proxies also exhibit different features in terms of volcanic responses and spectral ***-ring-based temperature reconstructions show stronger cooling responses to tropical volcanic eruptions,while non-tree-ring-based reconstructions suggest less robust volcanic responses,which may be related to dating uncertainties and low temporal resolution of the ***-ring width records tend to preserve a substantial proportion of high-frequency(hereas non-tree-ring proxies tend to capture a larger fraction of low-frequency(>200 years)*** are needed to reduce uncertainti

关键词： Millennial cooling trend Global climate change Proxy records Volcanic eruptions Spectral properties Common Era

A review on DFACS(II):Modeling and analysis of disturbances and noises

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Chinese Journal of Aeronautics 2024年第5期37卷 120-147页

作者： Chenglei YUE Bohan JIAO Zhaohui DANG Xiaokui YUE yonghe zhang Yuanqing XIA Li DUAN Qinglei HU Qifan LIU Pengcheng wang Ming GUO Zhansheng DUAN Bing CUI Chu zhang Xiaodong SHAO School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China Innovation Academy for Microsatellites Chinese Academy of SciencesShanghai 710699China School of Automation Beijing Institute of TechnologyBeijing 100081China institute of Mechanics Chinese Academy of SciencesBeijing 710043China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China School of Automation Science and Engineering Xi’an Jiaotong UniversityXi’an 710049China

This paper presents Part II of a review on DFACS,which specifically focuses on the modeling and analysis of disturbances and noises in *** Part I,the system composition and dynamics model of the DFACS were *** this paper,we discuss the effects of disturbance forces and noises on the system,and summarize various analysis and modeling methods for these interferences,including the integral method,frequency domain analysis method,and magnitude evaluation *** analyzing the impact of disturbances and noises on the system,the paper also summarizes the system’s performance under slight ***,we highlight current research difficulties in the field of DFACS noise ***,this paper provides valuable insights into the modeling and analysis of disturbances and noises in DFACSs,and identifies key areas for future research.

关键词： Drag-free DFACS Disturbance Analysis Noise Analysis Frequency Domain Analysis Performance Evaluation

Separation of Ephedrines Using 1-Butyl-3-methylimidazolium-tetrafluoroborate Ionic Liquids as Eluent in High-performance Liquid Chromatography (HPLC)

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Chinese Chemical Letters 2003年第6期14卷 603-604页

作者： Li jun he, Wen Zhu zhang, Bo WEN, Xia LIU, Sheng Xiang JIANG* lanzhou institute of Chemical physics, Chinese Academy of Science, lanzhou 730000 lanzhou Inst. of Chemical physics Chinese Academy of Science Lanzhou 730000 China

A simple, effective HPLC method for separation of ephedrines was achieved by using 1-butyl-3-methylimidazolium-tetrafluoroborate ionic liquid solution (0.1% v/v) as eluent at pH 3.0. The involved mechanism may be due to that the imidazolium cations can effectively shield the silanol groups of alkylsilica surface, thereby decreasing band tailing and increasing the separation efficiency.

关键词： Ionic liquid ephedrine HPLC.

Exploring hidden-charm and hidden-strange hexaquark states from lattice QCD

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Science china(physics,Mechanics & Astronomy) 2024年第1期67卷 30-37页

作者： Hang Liu Jinchen he Liuming Liu Peng Sun Wei wang Yi-Bo Yang Qi-An zhang INPAC Key Laboratory for Particle Astrophysics and Cosmology(MOE)Shanghai Key Laboratory for Particle Physics and CosmologySchool of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Maryland Center for Fundamental physics Department of PhysicsUniversity of MarylandCollege ParkMaryland 20742USA institute of Modern physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China Department of physics and institute of Theoretical physics Nanjing Normal UniversityNanjing 210023China Southern Center for Nuclear-Science Theory(SCNT) Institute of Modern PhysicsChinese Academy of SciencesHuizhou 516000China CAS Key Laboratory of Theoretical physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Fundamental physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for Theoretical physics Asia-Pacific Beijing 100049/Hangzhou 310024China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China School of physics Beihang UniversityBeijing 102206China

Based on five different ensembles of newly generated(2+1)-flavor configurations with pion mass of approximately mπ■(140-310)MeV,we present a lattice analysis of hidden-charm and hidden-strange hexaquarks with the quark content■.The correlation matrices of two types of operators with JPC=0++,0-+,1++and 1--are simulated to extract the masses of the hexaquark candidates,which are subsequently extrapolated to the physical pion mass and continuum *** results indicate that ground state masses are below the■threshold and provide a characteristic signal for the experimental discovery of hexaquark candidates,which may enrich the versatile structure of multiquarks;moreover,it is an indispensable step to decipher the nonperturbative nature of the fundamental interactions of quarks and gluons.

关键词： quantum chromodynamics lattice QCD multiquark states

Profile of the composition fractions in neutron stars

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Chinese Science Bulletin 2002年第8期47卷 632-634页

作者： LI Wenfei, zhang Fengshou & CheN LiewenCenter of Theoretical Nuclear physics, National Laboratory of heavy Ion Accelerator, lanzhou 730000, china institute of Modern physics, Chinese Academy of Sciences, lanzhou 730000, china Department of physics, Shangh Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Accelerator Lanzhou China institute of Modern physics Chinese Academy of Sciences Lanzhou China Department of physics Shanghai Jiao Tong University Shanghai China

The composition fractions of β-stable neutron stars and their radial distributions are investigated based on Skyrme-Hartree-Fock theory and Tolman-Oppenheimer-Volkoff (TOV) equation. It is found that a pure neutron interior with a radius of 3.5 km can exist in the neutron stars. When the radius is greater than 3.5 km, the fractions of the proton, electron and μ- appear and increase with the increment of the radius, then decrease after reaching their maximum at the radius of 8 km. These results make it possible to further study the thermal evolution and magnetic properties of the neutron stars.

关键词： neutron stars compositon fractions asymmetric nuclear matter equation of state Tolman-Oppenheimer-Volkoff equation.